DMMIC derivatization-assisted liquid chromatography-mass spectrometry method for metabolite profiling of the glutathione anabolic pathway in esophageal cancer tissues and cells

In this work, a new pyrylium derivatization-assisted liquid chromatography‒mass spectrometry (LC‒MS) method was developed for metabolite profiling of the glutathione anabolic pathway (GAP) in cancer tissues and cells. The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate (DMMIC) was used to label the amino group of metabolites, and a reductant of dithiothreitol (DTT) was employed to stabilize the thiol group. By combining DMMIC derivatization with LC‒MS, it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples, which had good linearity (R2 0.9981−0.9999), precision (interday precision of 1.6%−19.0% and intraday precision of 1.4%−19.8%) and accuracy (83.4%−115.7%). Moreover, the recovery assessments in tissues (82.5%−107.3%) and in cells (98.1%−118.9%) with GSH-13C2, 15N, and Cys-15N demonstrated the reliability of the method in detecting tissues and cells. Following a methodological evaluation, the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma (ESCC) and the effect of p-hydroxycinnamaldehyde (CMSP) on the GAP in KYSE-150 esophageal cancer cells. The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes, which can contribute to research on drugs and diseases.